### Errichto's blog

By Errichto, 6 years ago,

Hello Codeforces.

The CF Round #356 will happen on 8-th June (exact time). You will get five problems to solve in two hours. The round is rated.

I encourage you to read other problems if you don't like or can't solve something. The scoring distribution will be announced.

MikeMirzayanov and GlebsHP make the round possible. Also, thanks for Radewoosh, kostka, johnasselta, AlexFetisov and (more to be added?) for their amazing help. And I want to thank my girlfriend because there would be no Limak without her.

It's my first standard round. Still, you should get nice interesting problems. You will meet Limak, who is usually a little polar bear. Here he is, preparing one of problems.

I wish you great fun and no frustrating bugs.

EDIT — It's recommended for both divisions to read the Interactive Problems Guide before the round.

EDIT2, SCORING

div2: 500-1000-1750-2250-2750
div1: 750-1250-1500-2000-2500

EDIT3

The editorial with codes is ready.

WINNERS, congratulations!

and Division 2:

Thank you all for participation and see you next time. And regards from Limak, a bear.

• +687

 » 6 years ago, # |   +106 Looking forward to it! Such a long time since the last Div 1 round.
• »
»
6 years ago, # ^ |
-207

# So I give up the College Entrance Examination.

•  » » » 6 years ago, # ^ |   +86 I have seen your big font several times, and I think it isn't beautiful...
•  » » » » 6 years ago, # ^ |   -82 WOW
•  » » » » 6 years ago, # ^ |   -9 He's just very afraid of gaokao (高考) )))
•  » » » » » 6 years ago, # ^ |   +3 I apologize to all the English-speaking, below I will explain for Russian — that such GAOKAOПоясню для тех, кто не в теме, китайский ГАОКАО (高考) — это аналог российского ЕГЭ, только намного круче и ответственнее. И он проходит единым экзаменом в один день по всей программе, а не как в России разбит на предметы. Китайские школьники сдают этот экзамен на стадионах, гигантских актовых залах, часто не в свое городе, чтобы не было возможности "договориться". По результатам набранных экзаменов идет распределение во вузам, техникумам, училищам. Вроде тоже самое, что и у нас в России, НО — всего 5-7% выпускников китайских школ имеют возможность продолжить учебу в учебных заведениях. Остальные — работать на фабрики, поля и улицы! Поэтому истерика при сдаче просто сумасшедшая. При этом корочки ВУЗа дают высокий шанс на успешное будущее. На фото — проводы выпускников на экзамен Вот поэтому и я понимаю, почему КРУПНОПИШУЩИЙ нервничает ))
•  » » » » » » 6 years ago, # ^ |   0 WOW,this must be your small ID.
•  » » » 6 years ago, # ^ |   +16 Retarded
•  » » » » 6 years ago, # ^ |   -69 Don't curse.
•  » » » » » 6 years ago, # ^ |   +21 Go take the exam
•  » » » » » » 6 years ago, # ^ |   -41 I can take this exam in one years.But the Codeforces Round #356 (Div. 2) just has a time.
•  » » » » » » » 6 years ago, # ^ |   +1 Do you pay for the exam?
•  » » » » » » » » 6 years ago, # ^ |   -29 Don't need.
•  » » » » » » » » » 6 years ago, # ^ |   0 Bro Div. 2 Contests come out more than once a year; if you don't take the exam you're fucked
•  » » » 6 years ago, # ^ |   +2 why you can comment on this blog during the math exam...
•  » » » » 6 years ago, # ^ |   -22 Math is too simple for me. I have solved all the problem quickly, and hand in my paper ahead of schedule.
•  » » » » » 6 years ago, # ^ |   0 Indeed the JIBACANYANG,Orz
•  » » 6 years ago, # ^ |   0 Good luck and have fun! I need to finish Div 2 round.
 » 6 years ago, # |   -66 You are a programmer AND you have a girlfriend!!!you are my role model dude.
•  » » 6 years ago, # ^ | ← Rev. 4 →   -119 Who said that to you ?! I have two girlfriends :p
•  » » » 6 years ago, # ^ |   +31 do you like getting downvote?
•  » » » » 6 years ago, # ^ |   +12 do you like stay as " Newbie " !?
•  » » » » » 6 years ago, # ^ |   +70 hopeless coders should stay newbie
 » 6 years ago, # |   +745 "And I want to thank my girlfriend because there would be no Limak without her." congratulations on becoming a father!
•  » » 6 years ago, # ^ | ← Rev. 3 →   +364 Your comment is unbearable.EDIT: And I will kill you for this comment. I'm not going to help you with problems anymore. -_-
•  » » » 6 years ago, # ^ |   -56 Oh lighten up will ya
•  » » » 6 years ago, # ^ |   +44 Just bear with it.
•  » » » 6 years ago, # ^ | ← Rev. 2 →   0 [Deleted]
•  » » 6 years ago, # ^ | ← Rev. 2 →   +37 so his girlfriend is a polar bear?
•  » » » 6 years ago, # ^ |   -35 If that is true and the son is also a bear.... well, father is the one who rises the child. Kind of.
•  » » » 6 years ago, # ^ |   -11 No, a furry dinasor.
•  » » » » 6 years ago, # ^ |   -14 tourist 00
•  » » 6 years ago, # ^ |   +13 Why don't you thank that beautiful bear in your arms!? Btw I congratulate you in-advance :D
•  » » 6 years ago, # ^ |   +59 If you look closely you can see that Swistakk is also holding a little bear , i guess polar bear is the most wannabe female in Poland.
•  » » 6 years ago, # ^ |   +84 Now I'm even curious what will grow larger: the rating of your comment or the rating of this blog post.
•  » » » 6 years ago, # ^ |   +57 I and Errichto have closely observed that stout fight for two days xD.
•  » » » » 6 years ago, # ^ |   +6 I am also very curious if there is any relationship between the bear on your profile photo and Limak? :))
•  » » » » » 6 years ago, # ^ |   +3 No. That photo was taken back in 2011, way before Limak which I don't know how arose.
•  » » 6 years ago, # ^ |   +31 More votes on your comment than Errichto's blogpost . Looks like you are distributing your chocolates to downvote his blogpost and upvote your comment. :P
 » 6 years ago, # |   +5 You are my favourite problem setter! Too bad I will miss this round.
 » 6 years ago, # | ← Rev. 3 →   +38 Looking forward to "Bear and Forgotten Tree Girlfriend"! :) Anyway, this contest will surely be great as always. Thank you Errichto!
•  » » 6 years ago, # ^ |   +38 I wouldn't dare.
•  » » 6 years ago, # ^ | ← Rev. 2 →   0 As i see in Picture i think one of problems it would be "Bear and Forgotten Play-Cards" :)
•  » » 6 years ago, # ^ |   -26 I don't know what are you saying.
 » 6 years ago, # |   +2 Yes! The stories with Limak are always nice to read :)
 » 6 years ago, # |   0 It would be really nice if the round times would change this month just like last year. Ramadan month has started and Muslim contestants would be fasting, the contest kicks off just before 10 minutes of the beginning of Iftar time in my country (Iftar time is the time of day we get to eat).
 » 6 years ago, # |   +63 Errichto be like, Petr's getting closer to me on the contribution list, lemme prepare a new round and make his mission impossible lol . You always come with great problems, eagerly waiting for the round and hope I'll be able to participate, thank you .
•  » » 6 years ago, # ^ |   +51 You don't seem to know how big difference it is (currently between 162 and 175). Function contribution(upvotes on blog, upvotes on comments) is rather like a cubic root or logarithm rather than linear :P.
 » 6 years ago, # |   +13 I'm looking forward to it. You wrote some very nice problems in the past. I hope there will be many algorithmic problems :D
 » 6 years ago, # |   -18 Limak has a great subliminal message. Reverse it first: Kamil. It is the name of first Turkish polarbear manufacturer.
•  » » 6 years ago, # ^ |   +33 And its the name of the person who is preparing this round as well :)
•  » » 6 years ago, # ^ |   -12 Sen hala burdamisin la?
 » 6 years ago, # |   +10 my 1st div1 participation , am I gonna go back to div2 ?? I hope not :p
•  » » 6 years ago, # ^ |   +12 anyway , I like blue more than pink :v :v and it was a nice try
•  » » » 6 years ago, # ^ |   +1 You were purple before, not pink.
 » 6 years ago, # |   +6 Errichto, Your Problem Statements are So clear to me. I Solved Your problems in Hackerrank too. Thanks You.
 » 6 years ago, # | ← Rev. 2 →   -23 I am thinking of a replacement to the question "is it rated?" as it is overused any ideas?
•  » » 6 years ago, # ^ |   -31 how about "are there algorithmic problems?"
 » 6 years ago, # |   -23 Should I ask what I want to ask?
•  » » 6 years ago, # ^ |   -32 is it rated?
•  » » » 6 years ago, # ^ |   0 overused lemon turns sour and u know it
•  » » » » 6 years ago, # ^ |   -7 you have probably experienced it. Am I right?
•  » » » » 6 years ago, # ^ |   0 this is my first time experience.
•  » » » » » 6 years ago, # ^ |   0 yeah,i have
 » 6 years ago, # |   +3 Good Luck & Have Fun!
 » 6 years ago, # |   +128 We get it, you have a girlfriend.
 » 6 years ago, # |   +8 Tbh, Limak scares me. The later problems turn out to be DPs, which are scary for me. The quality of questions are great, though.
 » 6 years ago, # |   +4 That's GOOD
 » 6 years ago, # |   +22 Guess there will be statement like that:As Limak is a bear and he can't solve the problem by himself, so he ask you for help. Can you help him?
•  » » 6 years ago, # ^ |   0 i think it's a Plan to Strengthen relations Between Polar Bears and Humans
•  » » » 6 years ago, # ^ |   -8 or maybe the polar bears are some kind of alien and Errichto is one of their top spies sent to invade the earth he has already attacked Swistakk (notice the polar bear in his hands.) soon the polar bears might invade the earth. that would be unbearable
•  » » » » 6 years ago, # ^ |   +6 That's it, obviously!
 » 6 years ago, # |   +21 This may be strange, but I'm becoming a fan of Errichto, his posts, comments and problems. :)
•  » » 6 years ago, # ^ | ← Rev. 2 →   0 And he's quite handsome on his profile photo as well. <3It's going to be my first Div. 1 round ever, so let's see if I'll join your Errichto fan club after that :D
•  » » » 6 years ago, # ^ |   0 Yes he is indeed handsome!
•  » » » » 6 years ago, # ^ |   0 Hope you are female
•  » » » » » 6 years ago, # ^ |   +1 You guessed correct
 » 6 years ago, # |   +1 Wish me good luck guys I really feel like I'm gonna make it!!
•  » » 6 years ago, # ^ |   +79 What do you do... 50 push-ups for every Accepted ?
 » 6 years ago, # |   +10 I'm wondering if this little polar bear is preparing a problem about powers of prime numbers ? :p
•  » » 6 years ago, # ^ |   0 let's hope not
•  » » 6 years ago, # ^ |   +13 Wow, you guessed it right. Powers problem and primes problem.
•  » » » 6 years ago, # ^ |   +3 and he solved none of them
•  » » » » 6 years ago, # ^ |   0 ya i got good prediction :D , but bad rating :( ... but good prediction :D !!!
•  » » » 6 years ago, # ^ |   0 just Go and see my reply to kpw29 above and you will know who is also Guessed it somehow right
 » 6 years ago, # |   +5 i really hope that the pretests would be strong enough , because it's sucks when you spend a lot of time working on Problems and gets the same position of someone spent all the time refresh room page to hacks someone else solutions.
•  » » 6 years ago, # ^ |   +33 Hey, hacking is hard work! It's much harder to get 500 or 1000pts by hacking than solving a problem. Besides, once you get the hang of it it's super fun. Also, it's good to learn to code without relying on strong outside tests if you're ever gonna do coding outside of competitions.
•  » » » 6 years ago, # ^ | ← Rev. 3 →   -6 [Deleted]
•  » » » » 6 years ago, # ^ |   +54 Do you prefer it to fail on final tests?
•  » » » » » 6 years ago, # ^ |   +52 It's locked, at least he can live as happy for more 15-20 minutes :P
•  » » » » » 6 years ago, # ^ |   +4 Errichto You are merciful and you'll don't set tricky test case as a final test ...-_-... and maybe not :P
•  » » » » » 6 years ago, # ^ |   +13 I suppose we all would rather to be hacked way before the round ends, so we could fix it unless you have already locked the problem (which is a lost case anyway).
•  » » » » » » 6 years ago, # ^ |   0 exactly , I think hacking is a good thing
 » 6 years ago, # |   0 Limak is back!!! Hope to solve C!
 » 6 years ago, # |   0 if u look closely in the image there are 5 cards instead of 4, that means 5 questions in the round, and i think the card numbers are difficulty levels with one hidden.
 » 6 years ago, # |   0 Hope I can get my first 4/5 at your round, after 4 unsuccessful try -_-
 » 6 years ago, # |   -20 What do you mean by "your first standard round" — were the others prepared by you a non standard?
•  » » 6 years ago, # ^ |   +17 He has prepared Educational Rounds, VK Cup, India Hacks, Thanks-Round. Go to Problemsetting tab. So this is his first Standard Round.
 » 6 years ago, # |   0 It's fun that the last CF Round I took part in is on the Chinese Spring Festival, and this one is on the Dragon Boat Festival.
 » 6 years ago, # |   +16 Thumbs up for those playing cards from World Finals 2012! :)
 » 6 years ago, # |   +28 It's recommended to read the Interactive Problems Guide prepared by Mike Mirzayanov.
•  » » 6 years ago, # ^ |   0 :( :( :( i was expecting some normal problem
•  » » » 6 years ago, # ^ |   +35 Don't worry, you will get four normal problems.
•  » » » » 6 years ago, # ^ |   +12 Maybe four is not enough for him..
•  » » » » » 6 years ago, # ^ |   0 wow, you can feel me my bro -_-
•  » » 6 years ago, # ^ |   0 Wow this doubles the fun. This is awesome.
•  » » 6 years ago, # ^ |   +32 Isn't the Interactive Problems are suitable for Educational Round . ( just my thought )
•  » » 6 years ago, # ^ |   +1 So still not so standard round :P
 » 6 years ago, # |   +8 i think the second problem will be interactive as second card is hidden in the image .
•  » » 6 years ago, # ^ |   +2 The interactive problem will be both for Div. 1 and Div. 2, according to the main post. So, it cannot be the Div. 2's second problem.
•  » » » 6 years ago, # ^ | ← Rev. 2 →   0 it can be 4th also
 » 6 years ago, # | ← Rev. 2 →   +58 So it is not a standart round as well :p
 » 6 years ago, # |   +3 Having interactive problems adds to fun of Competitive Programming. :)
•  » » 6 years ago, # ^ |   0 yes I love interactive problems :)
 » 6 years ago, # |   0 It's about time I left the green phase without a second comebackGood luck everyone
•  » » 6 years ago, # ^ |   0 Good luck, I hope that too for myself !
 » 6 years ago, # |   +11 Oh, div2 C scores 1750, I have a bad feeling..
•  » » 6 years ago, # ^ |   +1 C is easy just like typical rounds. But D and E, too difficult for me. the 5th unsuccessful attempt to get a 4/5.
 » 6 years ago, # |   +8 Feels like experimental round, poor you Errichto
 » 6 years ago, # | ← Rev. 2 →   +17 I had great fun solving Div2/C. Thanks for the nice problems, Errichto!
 » 6 years ago, # | ← Rev. 5 →   -16 My solution to problem C.Whenever i tried to submit it , my browser get stuck on the same page. More interesting part is that submitting this solution to any other problem results the same.
•  » » 6 years ago, # ^ |   0 Your solution says 2 is composite
 » 6 years ago, # |   -38 Why am I getting WA for Div2 C?int sieve[1000]; set st;bool isPrime(int num) { return (st.find(num) != st.end()); }int main() { //t(); st= { 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97 }; vi v; for (int i = 2; i <= 10; i++) { cout << i << endl; fflush(stdout); string s; cin >> s; if (s == "yes") v.pb(i); } if (v.size() == 0) { cout << "prime" << endl; fflush(stdout); return 0; } if (v.size() == 1) { if (!isPrime(v[0])) { cout << "composite" << endl; fflush(stdout); return 0; } else { cout << v[0] * v[0] << endl; fflush(stdout); string s; cin >> s; if (s == "yes") { cout << "composite" << endl; fflush(stdout); return 0; } else { cout << "prime" << endl; fflush(stdout); return 0; } } } if (v.size() > 1) { cout << "composite" << endl; fflush(stdout); return 0; } return 0; }
•  » » 6 years ago, # ^ |   0 Consider number 74 = 2 * 37 for example.
 » 6 years ago, # |   0 that difficulty gradient though :P
 » 6 years ago, # |   0 i got stuck on C because i didn't take perfect squares in account
•  » » 6 years ago, # ^ |   +3 It wasn't covered by pretests.
•  » » » 6 years ago, # ^ |   0 but i was getting wrong answer because of that probably
 » 6 years ago, # |   +7 How to solve Div 2 — D?
•  » » 6 years ago, # ^ |   +8 What I coded up and finished a bit after the end was this:First, generate first few terms of sequence, and oeis the rest: http://oeis.org/A055402Then hardcode those values, and for a given m pick the best value you can. Call this best value v. Decompose v into its cubes, then(from highest to lowest) try incrementing each cube(n^3 becomes (n+1)^3) while making sure the sum doesn't exceed the given m. Then output this sum. I didn't get to submit, so I'm not sure if this is completely correct
•  » » » 6 years ago, # ^ |   0 Oh, I knew I weren't the only one who tried to look up this very sequence in OEIS. Came up with almost the same approach and got WA 4 (see 18325136).
 » 6 years ago, # |   0 What an amazing round! First time to solve 3 :D Thanks for amazing tasks! Keep it up !Cheers
 » 6 years ago, # |   -6 According to me , the 3rd problem should be able to differentiate between coders and the number of people who solve should be <=700,800. That was definitely not the case today.
 » 6 years ago, # | ← Rev. 2 →   0 2 of my submissions were submitted at the exact same second . Can one of these be removed while considering penalty >.<
•  » » 6 years ago, # ^ |   0 First one will be skipped
•  » » » 6 years ago, # ^ |   0 Both gave me a WA >.<
 » 6 years ago, # |   0 Problem Div2 C was really easy for hacks, because it had week pretests! For example, I hacked two people using "94" as a hack because they didn't check for 47. Another hack was "49", so no perfect squares.
 » 6 years ago, # |   +1 TNX for your perfect contest and fast editorial guys.
 » 6 years ago, # | ← Rev. 3 →   +73 After try spending 1 hour and 45 minutes on Div1-B:I'll need to train harder next time...
•  » » 6 years ago, # ^ |   0 Dont Worry the number of the contests coming are more than those which have passed :) All of us needs to train harder :)
•  » » 6 years ago, # ^ | ← Rev. 2 →   0 I couldn't think of a legit solution either...I ended up using a really sketchy solution in which I check the 500000 numbers below m and take the optimal value (can't prove it's correct, let's see if I AC).edit: darn got WA
•  » » » 6 years ago, # ^ |   +3 Did the same thing, WA on test 20 :|
•  » » 6 years ago, # ^ |   +29 Why didn't you try div1-C then?
•  » » 6 years ago, # ^ |   +25 Spent whole contest trying to solve B and then solved C in 20 minutes after the contest....
 » 6 years ago, # |   +15 Errichto when can we expect system testing? In 5 minutes or in a hour?
•  » » 6 years ago, # ^ |   0 in 2 minutes :D
 » 6 years ago, # |   0 Hm, I guess xiaoai finally concluded that her skin is more important than coding.
 » 6 years ago, # |   0 I want to know why my solution got run time error for div2 b. can anyone pls take a look? link to submission Thanks
•  » » 6 years ago, # ^ |   0 You are reading more input values than you should/have.
•  » » » 6 years ago, # ^ |   0 Yes thanks. Corrected and AC
 » 6 years ago, # |   0 I completely forgot to input m as a long long for problem D.At least my solution probably had a bug somewhere else!
 » 6 years ago, # |   +22 Again, A massive gap between Div.2 C and Div.2 D ...
•  » » 6 years ago, # ^ | ← Rev. 2 →   +7 I think it's not a good problem set.........No layering
 » 6 years ago, # |   0 I managed to find number of cubes in D and minimal volume. Was it the right way or this information is useless?
 » 6 years ago, # |   +7 Forgot «47» in C... short div[] = {2, 3, 4, 5, 7, 9, 11, 13, 17, 19, 23, 25, 29, 31, 37, 41, 43, 47, 49} Frustraiting...
•  » » 6 years ago, # ^ |   +5 Same here, I omitted 19. Really infuriating...
•  » » » 6 years ago, # ^ |   0 That kind of information you could just google: https://www.google.ru/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=primes%20less%20than%20100
•  » » 6 years ago, # ^ |   +6 That's why you just write a prime sieve and let the computer do it for you, it won't forget anything :)
 » 6 years ago, # |   0 Can anyone please explain how to obtain the 0.916666666667 in the 3rd sample test of problem D?
•  » » 6 years ago, # ^ |   +8 If I remember correctly, you should twice use BCD in city 1. If you get distance 0 then you win immediately. Otherwise, for sure Limak moved between cities 2 and 3 — guess one of them.
 » 6 years ago, # | ← Rev. 2 →   0 hacked two solutions in div2 C and then realized that i was screwed ! 25 and 49 will hunt me down tonight . :(
 » 6 years ago, # |   -79 Now-a-days contests have become extremely rare. And then to provide a contests like today is so disappointing...To do so much upsolving preparing for contests..for what? An interactive problem that almost 70% of the candidates can solve? Noooo...This is just not done..
•  » » 6 years ago, # ^ |   +1 Speed matters too you know !
•  » » » 6 years ago, # ^ |   0 Absolutely....I wasted too much time on C and got stuck on 1200 position...if i would have solved it faster...my position would have been under 500 as I had a lot time for C :(
•  » » » » 6 years ago, # ^ |   +13 You could also use hacks on Div2 C even if you had lost some time, there were many participants with wrong code because the pretests were weak. After submitting my first 3 problems I ended up being somewhere near place 250, but with 3 hacks I got to the place 47 and thus I am Div1 now :)
•  » » 6 years ago, # ^ |   0 If you would've solved problem D, you wouldn't be complaining. Keep upsolving, and you will keep do better and better :)
 » 6 years ago, # |   +46 Thank you for a wonderful round!)
 » 6 years ago, # |   +19 Thank you very much, Errichto! I loved the problems!I came up with the efficient approach for C right after the contest ended and it took me some 10-15 minutes more to code it, but I enjoyed the contest nevertheless :D
 » 6 years ago, # | ← Rev. 3 →   +30 my eyes almost got cancer from debugging this.. only realizing my l and j is swapped after the contest is finish..
•  » » 6 years ago, # ^ |   +25 Your fingers deserve cancer for writing this.
•  » » » 6 years ago, # ^ |   +8 What about my fingers? =) 18321088
•  » » » 6 years ago, # ^ |   +33 Very mean. Maybe you're not handsome after all.
•  » » » 6 years ago, # ^ |   +30 nobody deserves cancer :)
•  » » » 6 years ago, # ^ |   +31 Then , see this 18323430
•  » » » » 6 years ago, # ^ |   0 Respect for this guy :D
•  » » » » » 6 years ago, # ^ |   0 I felt like this Code won't pass when I was looking for hacks.But I gave up on reading this code, but soon I realized it was a big mistake as the test was pretty trivial, I think he mistyped the last else block, but how can he ! He must be god or something!
•  » » » » 6 years ago, # ^ |   0 WTF
•  » » » » 6 years ago, # ^ |   0 LOL
•  » » » » 6 years ago, # ^ |   0 18317238I hate 93 :(
•  » » 6 years ago, # ^ |   0 For me polishing E was so immersing, that I've forgotten (but coded) to submit A. Things happen.
 » 6 years ago, # |   +7 The waiting for rating change has just begun.
•  » » 6 years ago, # ^ |   0 ...and it's over
 » 6 years ago, # |   +24 Thank you for participation and for kind words. Also thanks for bad words (as long as it's something constructive/reasonable). Btw. div2 participants can now check again a picture from the blog. Do you know why is there one card hidden?
•  » » 6 years ago, # ^ |   0 Congratz for the contest, it was really good in my opinion (maybe difficulty raise was a little too high between div2.C and div2.D, but still I really enjoyed this contest).
•  » » 6 years ago, # ^ |   +27 Because you hided it??
•  » » 6 years ago, # ^ |   0 So , why is one card hidden ?
•  » » 6 years ago, # ^ | ← Rev. 3 →   +9 Because SpoilerIt's one of samples in div2-A and the hidden card should contain a number 1. But there are no cards with this number, there are only 2,3,...,10.
 » 6 years ago, # |   +5 Awesome contest!!! :D Solved 3. Coded brute force dp for 4th one but failed to find a tiny bug in time which was resulting in wrong answers for the tescases :/
 » 6 years ago, # |   -32 My view of the points system this round 500 — 750 — 1250 — 2500 — 3500Honestly, I miss the dynamic scoring.
•  » » 6 years ago, # ^ |   +6 How would it affect your position?(but yeah, I see that the difference between C and D was too big)
•  » » » 6 years ago, # ^ |   +5 it was tooooo big :(
 » 6 years ago, # |   0 18329338 -_- It gives a proper output in CodeBlocks but wrong in CodeForces !!! But why ?
•  » » 6 years ago, # ^ |   0 Array overbound gives unexpected result.
•  » » » 6 years ago, # ^ |   0 Thanks .
 » 6 years ago, # |   0 a moment of silence :D
•  » » 6 years ago, # ^ |   0 why?
 » 6 years ago, # |   +14 This contest was outstanding.It's the first time I solve C during the contest and I turned green :)thank you Errichto.hope to see you make new contests soon. :)
 » 6 years ago, # | ← Rev. 4 →   0 problem B: 21 test because the judge says my code returns 46 when actually my code returns 39?
 » 6 years ago, # |   0 Awesome round, especially Div2/C. Looking forward to seeing more interactive problems in the future! :)
 » 6 years ago, # |   0 Very interesting round! The most interesting round in a while for me. Thanks for the interesting problems! Wish I could've solved div 1 C :/
 » 6 years ago, # | ← Rev. 2 →   0 thanks Errichto for div2 problem C. this is the first time i solved C during contest time.and also thanks MikeMirzayanov for the post before contest starting .
 » 6 years ago, # |   +18 I think Div 1 C/D may be easier than Div B :)